Showing papers on "Linear particle accelerator published in 1971"
TL;DR: In this paper, a magnetic spectrometer to analyze the elastically and inelastically scattered electrons in combination with the Tohoku University 300-MeV electron linear accelerator is described with emphasis on its electron ladder and the data acquisition system.
14 citations
Patent•
02 Feb 1971
TL;DR: In this paper, a method for the acceleration of ions in linear accelerators consisting of a cavity resonator 1 and drift tubes 2 employing a standing r.f. electromagnetic wave was described.
Abstract: The present invention relates to methods for acceleration of ions in linear accelerator and to a linear accelerator realizing this method. The method for the acceleration of ions in linear accelerators consisting of a cavity resonator 1 and drift tubes 2 employing a standing r.f. electromagnetic wave, according to the invention, is characterized in that the resonator is excited in the E011 mode enabling the energy of the accelerated-ion beam to be controlled continuously by establishing a region with a uniform distrubution of the accelerating field and by varying the extent of that tregion. This method can be realized by a linear accelerator comprising a cavity resonator 1 with drift tubes 2; tuners 3 arranged on the side wall of the resonator 1; an additional tuning means made in the form of a conducting post 4 installed in an end wall of the resonator 1 near its side wall parallel with the axis of the resonator and capable of being moved along that axis.
12 citations
TL;DR: The 10C MeV electron accelerator and facility, at Livermore have been designed for undertaking investigations in neutron physics and nuclear photoreactions as discussed by the authors, which has required versatility in the performance of the accelerator and in the layout of the beam transport system.
Abstract: The 10C MeV electron accelerator and facility, at Livermore have been designed for undertaking investigations in neutron physics and nuclear photoreactions. This has required versatility in the performance of the accelerator and in the layout of the beam transport system. The accelerator is a 5-section S-band device with bearm. pulse capability of 5ns, lOA at 1800 pps to 3?s 650 ma at 300 pps. A tungsten converter after the third section produces a positron beam capable of acceleration to 80 MeV. The accelerator can operate in the transient or steady state modes. The magnets used to steer the high current pulses are achromatic and can pass a momentum spread of ± 15%. Other beam lines are achromatic and can pass a momentum spread of ± 5%.
10 citations
Journal Article•
TL;DR: In this paper, two computer programs written for investigating space charge effects in proton linear accelerators are presented Both use the dynamics equations derived by Drs P Lapostolle and B Schnizer: the way these equations have been practically treated is explained Details are given on the two programs: the first one is based on particle to particle interaction, while the second one benefits from a continuous equivalent distribution
Abstract: Two computer programs written for investigating space-charge effects in proton linear accelerators are presented Both use the dynamics equations derived by Drs P Lapostolle and B Schnizer: the way these equations have been practically treated is explained Details are given on the two programs: the first one is based on a particle to particle interaction, while the second one benefits from a continuous equivalent distribution Results given by both programs are compared and contrasted to Dr R Chasman's previous results As an application, the problem of the influence of injection energy on linac performance is partially treated
10 citations
TL;DR: In this paper, a new and very effective technique for accelerator field control is demonstrated, using a feed-forward control loop to complement a standard feedback controller, where the accelerated beam current envelope, which acts as a load disturbance on the accelerator field amplitude and phase, is detected upstream from the module to be controlled.
Abstract: A new and very effective technique for accelerator field control is demonstrated, using a feedforward control loop to complement a standard feedback controller. The accelerated beam current envelope, which acts as a load disturbance on the accelerator field amplitude and phase, is detected upstream from the module to be controlled. Due to differences in propagation velocity in the accelerator and external cables, true anticipating control is possible by feeding the current signal forward to the controller. In tests with full beam loading (22%) in the first 201.25 MHz tank at LAMPF, peak amplitude error was reduced to 0.4% and settling time to 20 ?sec at beam turn-on.
9 citations
TL;DR: In this paper, it was shown that under certain assumptions the beam-RF system with no feedback control is stable against center-of-charge oscillations if the cavity resonance frequency, wo, lies in restricted ranges.
Abstract: The stability of a beam in an RF accelerating cavity in a storage ring or circular accelerator has been studied by K. Robinsonl* 2 and many others. Robinson has found that under certain assumptions the beam-RF system with no feedback control is stable against “center-of-charge” oscillations if the cavity resonance frequency, wo, lies in restricted ranges. In particular, if ~0 is less than the RF frequency, Y, and the beam current is less than a critical value, IBC, the system is always stable. It may be possible, however, to increase the value of IBC and the range of stable frequency by the use of feedback. This possibility has been investigated for a beam-RF system with feedback control of the cavity voltage amplitude and phase.
9 citations
TL;DR: The first section of the 1.3 GHz superconducting linac, being constructed for the proposed 600 MeV microtron, was installed into the cryostat and operated as an accelerator for the first time as mentioned in this paper.
Abstract: The first section of the 1.3 GHz superconducting linac, being constructed for the proposed 600 MeV microtron, was installed into the cryostat and operated as an accelerator for the first time. An electron beam of 270 keV, chopped to a select phase spread of 6 degrees, was injected into the 3?/2 niobium structure and accelerated to 1 MeV with an input of 30 watts of microwave power at 4.2°K. The accelerated beam was 2 mm in diameter 3 meters beyond the accelerating section. The energy spread was less than 1%. The niobium section had not been outgass d at high temperature and had a Q of 1.4 x 108. The energy gain seemed to be limited to about 1 MeV per foot by field emission, as indicated by the rapid rise of the x-ray yield as the microwave power was increased.
8 citations
Patent•
22 Oct 1971
TL;DR: In this paper, a cylindrical cavity resonator was used for bunching in linear accelerators, where a velocity modulation cavity was used to modulate the particles and a drift space was used by bunching the particles.
Abstract: The bunching device in accordance with the invention is essentially constituted by a cylindrical cavity resonator, which advantageously replaces the conventional device encountered in linear accelerators, including a velocity-modulation cavity for modulating the particles and a drift space for bunching said particles.
7 citations
6 citations
TL;DR: A toroidal induction monitor was designed for the Oak Ridge Electron Linear Accelerator (ORELA) to provide a visual display of beam current pulses having peak amplitudes up to 15 amp with widths ranging from 3 to 200 nsec as mentioned in this paper.
Abstract: A toroidal induction monitor was designed for the Oak Ridge Electron Linear Accelerator (ORELA) to provide a visual display of beam current pulses having peak amplitudes up to 15 amp with widths ranging from 3 to 200 nsec. To achieve rise times of about 1 nsec, the monitor was designed to utilize the influence of the electric field of the electron bunch to improve the response time of the magnetically induced output pulse. The final monitor design consists of a Ferroxcube 400T750, ferrite toroidal core of 1.25 in. ID wound with ten symmetrical turns of AWG 26 Formvar copper wire. The toroid is mounted at the end of the last acceleration tube in an assembly which includes a 0.9-in. ID collimator preceding the toroid. For simplicity of mechanical design, the toroid is operated at the vacuum level of the acceleration tube.
6 citations
TL;DR: A program is presently in progress for the modification of the Hilac to make possible the acceleration of ions of all masses to a maximum energy of 8.5 MeV/N as mentioned in this paper.
CERN1
TL;DR: In this article, the authors show that the space-charge defocusing force is an appreciable fraction of the average external focusing force (1/3 for the CERN line), which leads to significant departures from the beam envelope calculated for zero current.
Abstract: Space-charge effects can be large in transport lines. For the 50 MeV proton lines at Brookhaven or CERN, an average current of 100 mA corresponds to a peak current of 2.5 A due to the short bunch length (N 2 cm). As a result, the space-charge defocusing force is an appreciable fraction of the average external focusing force (1/3 for the CERN line), which leads to significant departures from the beam envelope calculated for zero current, i.e. waists as moved, aperture requirements are increased, and the beam is mismatched for the following synchrotron. In addition, 'longitudinal space-charge forces cause an increase in energy spread, typically an increase of i 200 or i 300 keV for the CERN line. Finally, non-linear components of the space-charge force twist and filament the distribution leading to an increase in emittance.
TL;DR: In this paper, the Desy electron-positron linear accelerator (DESY linac) has been used for high-current injection to the 7 GeV synchrotron and future electron-positionitron injection into a 3 GeV storage ring.
Abstract: Measurements made during acceptance testing of the Desy electron-positron linear accelerator Indicate performance approaching the design value. The purpose of the linac is high-current Injection to the 7 GeV synchrotron and future electron-positron Injection into a 3 GeV storage ring now under construction. The linac consists of 12 5.2 meter constant-gradient sections driven by SLAC-type (TV) klystrons operating at 24 MW. Electron pulsed currents of 135 mA at 514 MeV In a 1% energy bin were measured during 24-hour tests. A positron current of 1.4 mA within an energy spread(?E/E) of 1% bin and an emittance of 1? mRad.cm at 385 MeV has been measured. Electron load line and emittance data have been taken. Beampulse shortening of the SLAC-type occurs above 250 mA.
TL;DR: In this article, the design and construction of the Niobium accelerating structure, refrigerator, dewar, helium distribution system, and the injector and control system are described and discussed.
Abstract: The design and construction of the accelerator is discussed. In particular, the design of the niobium accelerating structure, refrigerator, dewar, helium distribution system, and the injector and control system are described.
TL;DR: In this article, the TWR equations of the Leapfrog superconducting accelerator with beam loading were derived from the equations for the standing wave supercondensing accelerator with a beam load.
Abstract: with the case for arbitrary loss usually presented. The TWR equations are shown to take the identical form, in the absence of a mismatch, as the expressions for the standing wave superconducting accelerator with beam loading. 6 At SLAC a twefoot long TWR test accelerator (project Leapfrog) is currently under construction. A thorough understanding of TWR behavior is necessary for the successful design and operation of such a device. In the following sections of this paper the basic relations describing the behavior of the TWR accelerator are summarized. In the final section some implications of the theory for the Leapfrog accelerator are given. The description of TWR behavior as presented here is necessarily brief. Details of the derivations and a more extensive discussion are given in Ref. 7.
TL;DR: Spence, D.A., Gavin, B.F., Peters, R., Reginato, L.L., Smith, B., and Wolgast, R.C. as mentioned in this paper
Abstract: Author(s): Spence, D.A.; Gavin, B.F.; Peters, R.; Reginato, L.L.; Smith, B.H.; Wolgast, R.C.
TL;DR: The ALICE hybrid accelerator as mentioned in this paper is a hybrid accelerator made of a linac injector connected to an AVF cyclotron, which is used in the search for new heavy elements.
TL;DR: It is useful for routine measurements and adjustments to control the field flatness of an x-ray beam from a linear accelerator, and also for setting accelerator working conditions to produce electron beams with flat fields at energies between 3 and 10 MeV.
Abstract: It is useful for routine measurements and adjustments to control the field flatness of an x-ray beam from a linear accelerator (Naylor and Chiveralls 1970), and also for setting accelerator working conditions to produce electron beams with flat fields at energies between 3 and 10 MeV. The instrument has the advantage that differences in dose rates can be monitored while adjustments are being made to the accelerator.
TL;DR: The theory of particle bunch formation by means of velocity modulation, produced by single gap cavities, is customarily based on a ballistic analysis as mentioned in this paper, but due to the ready availability of computers, it is convenient to investigate velocity modulation including space charge forces using relativistic kinematics.
Abstract: The theory of particle bunch formation by means of velocity modulation, produced by single gap cavities, is customarily based on a ballistic analysis. Owing to the ready availability of computers, it is convenient to investigate velocity modulation including space charge forces using relativistic kinematics. This report presents the results of a systematic examination of bunching parameters.
TL;DR: In this paper, the authors used time-of-flight techniques with a silicon surface barrier detector and a polyethylene radiator to determine the neutron flux from the Oak Ridge electron linear accelerator in the energy region between 200 keV and 7 MeV.
Abstract: Time‐of‐flight techniques have been used with a silicon surface barrier detector and a polyethylene radiator to determine the neutron flux from the Oak Ridge electron linear accelerator in the energy region between 200 keV and 7 MeV. The 200 mm2 surface barrier detector at 40 m and constant fraction timing electronics are used to measure time of flight, from which the neutron energies are inferred. A Monte Carlo program has been written to determine the efficiency, timing, and energy characteristics of the monitor system.
TL;DR: In this article, a variety of options can be divided into three categories: improvements and upgrading of the existing linac; energy and duty cycle increases by means of beam storage in a recirculation scheme, and various colliding beam devices.
Abstract: In June 1971, the SLAC accelerator will have completed its first five years of operation. The machine has recently achieved records of energy (22.1 GeV), peak beam current (82 mA at a 1.6 ..mu..s pulse length) and average beam power (880 kW). The demand for major accelerator innovations and improvements is becoming increasingly strong. Some of the recent ideas on this subject are summarized. There are a variety of options, and these can be divided into three categories: (a) improvements and upgrading of the existing linac; (b) energy and duty cycle increases by means of beam storage in a recirculation scheme, and (c) various colliding beam devices. The first category includes increasing beam energy by addition of rf power or increasing duty cycle by modifying the modulators; it also includes an rf monochromatizer which could sharpen energy spectrum by a factor of 30. The second category involves a scheme which would increase beam energy by ''storing'' the electrons in a recirculator until they can be re-injected and reaccelerated by the accelerator a second time. The third category comprises the possibility of colliding the linac beam with the beams stored in the SLAC storage ring (SPEAR) or of colliding the linacmore » beam with itself.« less
CERN1
TL;DR: In this paper, a description of all beam diagnostics equipment for the CERN PS Booster is given, including a computerized system of position pick-up electrodes, a 900 MHz electromagnetic pickup station, the fast measurement of the betatron-tune and the measurement line for the ejected beams.
Abstract: A description of all beam diagnostics equipment for the CERN PS Booster is given. The following items are discussed in more detail: -a computerized system of position pick-up electrodes, -a 900 MHz electromagnetic pick-up station, -the fast measurement of the betatron-tune and -the measurement line for the ejected beams (spectrometry and emittance measurements).
TL;DR: In this paper, the authors describe the central control system now being built and used to operate the completed parts of the NAL accelerator, which has several levels of organization, and it is desirable that control be possible at more than one level, in order to avoid shutdowns caused by higher-level equipment failures.
Abstract: This paper describes the central control system now being built and used to operate the completed parts of the NAL accelerator. This control system may be of some interest because new methods of monitoring and control are made necessary by the greatly increased size and complexity of the NAL accelerator compared with other synchrotrons. The primary design goal for the NAL control system is that eventually, during routine operation, one person be able to operate the entire accelerator: preaccelerator, linear accelerator, booster synchrotron, main synchrotron and beam-extraction and transport systems. But it is also necessary that several operators be able simultaneously to interrogate and control different parts of the accelerator for maintenance, diagnosis of equipment problems, bringing new devices on, and for accelerator-development studies. To attain these goals, a computer-assisted system has been designed and is being built. This system has several levels of organization, and it is desirable that control be possible at more than one level, in order to avoid shutdowns caused by higher-level equipment failures. The system must also be flexible enough to accommodate the new devices we expect will be added as the accelerator is developed. This paper includes an overall description of the control system, and details of some of its special features.